Thermal Setting of Knit Fastener Loops with Bicomponent Yarns
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Solution Overview
Problem
Existing circular knit materials used for hook and loop fasteners suffer from high stretchability and require additional binder coatings, which increase cost and reduce air permeability.
Innovation Solution
A method involving knitting a pile yarn and ground yarns to form a stretchable fabric, using bicomponent yarns with distinct polymers, and applying heat to cause resin flow into interstices, reducing stretchability and enhancing air permeability while maintaining hook-engageable loops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If circular knit materials are used for hook and loop fasteners, then the fabric is stretchable and comfortable, but the stretchability is too high and dimensional stability is poor
Solution Approach 1:
The patent applies heat treatment to change the physical state of the polymer filaments, causing them to melt and bind together. This thermal parameter change transforms the fabric from a stretchable state to a dimensionally stable state while preserving the loop structure for fastening functionality
Solution Approach 2:
The invention uses bicomponent yarns containing two different polymers with distinct melting points. This composite material structure allows selective melting of one component to bind the fabric ground, while the other component maintains the structural integrity and stretchability characteristics
2Stability of the object's composition
If binder coatings are applied to stabilize circular knit fabrics, then dimensional stability improves, but air permeability decreases and cost increases
Solution Approach 1:
The patent removes the need for external binder coatings by integrating the binding function directly into the yarn structure. The melt-adhering polymer within the bicomponent yarn serves as an internal binder, eliminating the harmful coating layer and preserving air permeability
Solution Approach 2:
The melt-adhering polymer acts as an intermediary substance that binds the fabric ground together through heat activation. This internal intermediary replaces external binder coatings, maintaining fabric porosity and breathability while achieving dimensional stability
3Stability of the object's composition
If binder coatings are applied to stabilize circular knit fabrics, then dimensional stability improves, but manufacturing cost increases
Solution Approach 1:
The patent combines the yarn structure and binding agent into a single integrated component. The bicomponent yarn includes both structural and binding functions, eliminating the need for separate binder coating processes and reducing manufacturing steps
Solution Approach 2:
The fabric stabilizes itself through the heat-activated binding properties of the integrated polymer. The melt-adhering component automatically binds the ground knits when heat is applied, eliminating the need for external binder materials and additional coating processes
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method produces a stable, low-cost fastener with improved dimensional stability and air permeability, eliminating the need for binder coatings and maintaining functional integrity under tensile loads.
Implementation Method 1
applying heat to cause resin of the sheath of the bicomponent yarn filament to flow into interstices of the fabric ground
Implementation Method 2
allowing the fabric to cool, such that the cooled fabric ground is less stretchable in two orthogonal directions after setting than before setting
Implementation Method 3
applying sufficient heat to cause resin of the sheath of the bicomponent yarn filament to flow into interstices of the fabric ground
Data Source
AI summary
A method of making a loop fastener product features knitting, such as by circular knitting, a pile yarn and one or more ground yarns to form a stretchable knit fabric having loops of the pile yarn extending from a knit ground, with the ground yarns including polymers of differing melt temperatures. The knit fabric is then held in a desired state while the fabric is set by first applying sufficient heat to cause the lower melt temperature resin to flow into interstices of the fabric ground, and then allowing the fabric to cool. The cooled fabric ground is less stretchable in two orthogonal directions after setting than before setting, has a greater air permeability after setting than before setting, and has hook-engageable pile loops extending from bound interstices.